A sealing arrangement of this kind and a sealing ring of this kind are disclosed in the earlier application DE 10 2016 012 552.7.
The electrically insulating casing has a material thickness that is constant in all peripheral regions around the electrically conductive core. The casing has a relatively low material thickness and rests flat on the core.
The wear detector comprises an electric measurement device that is designed as a capacitive measurement device. A measurement principle of this kind is based on an electric voltage being applied between the surface to be sealed of the machine element to be sealed and the core of the sealing ring, and the electrical capacitance between the surface to be sealed and the core being determined. Variables that influence the electrical capacitance are the dielectric constant of the casing and the radial distance between the surface to be sealed and the core.
Sealing rings having a sealing lip made of a sealing material, in particular dynamically loaded sealing lips, wear down when the sealing ring is used as intended. Wear of this kind may lead to there initially being a leak in the sealing arrangement and then to a breakdown of the entire sealing system.
When the material thickness of the sealing lip, which is part of the casing, changes as the wear becomes more severe, the electrical capacitance between the surface to be sealed and the core of sealing ring also changes, this change in the electrical capacitance being determined by suitable analysis electronics.
As is disclosed in the earlier application, gradual changes in the operating behavior of the sealing ring and gradual wear of the sealing lip can therefore also be detected. The state of the sealing ring is thus continuously monitored.
A further sealing arrangement is known from DE 10 2007 007 405 B4. The known sealing arrangement comprises a dynamically loaded sealing ring and an electric apparatus for detecting the state of wear of the sealing ring, the sealing ring consisting of an electrically conductive first sealing material, to which an electrically non-conductive second sealing material is attached, which is in sealing contact with the surface to be sealed of a machine element to be sealed. The surface to be sealed is electrically conductive, in the same way as the first sealing material.
When the second sealing material is completely worn, the electrically conductive surface to be sealed touches the also electrically conductive first sealing material, and a circuit for indicating complete wear, i.e. for indicating the destruction of the sealing ring, is closed.
In the case of such a configuration of the sealing arrangement, it should be noted that it is not possible to detect a gradual change in the state of the sealing ring. As a result of the closure of the circuit, it is merely indicated that the sealing ring is no longer in working order and must be immediately replaced.